A general portable terminal includes: a display panel; a circuit board on which an electronic component is mounted; and a rechargeable battery that supplies power to the circuit board and the display panel. Besides, the circuit board and the rechargeable battery are housed in a cabinet, and the display panel is disposed on an open surface of the cabinet. Here, the circuit board is disposed on a rear side of the display panel, and the rechargeable battery is disposed on a rear side of the circuit board. And, the electronic component and the display panel operate on the power supplied from the rechargeable battery. However, the electronic component generates heat during use of the portable terminal; accordingly, there is a problem that the heat generated from the electronic component locally travels to the display panel to deteriorate display quality.
A patent document 1 discloses a cooling device for a portable terminal. As to this cooling device, a conductive sheet, which is flexible and excellent in heat conduction in a surface direction, is covered on an electronic component in a cabinet. In this way, heat from the electronic component travels to the cabinet via the conductive sheet, so that the electronic component is cooled.